A very old cow drinking trough observed in a field. I found this example on one of my cycle routes, its constructed of cement which reveals that its quite old, probably pre WWII. Such items have for a long time been constructed of galvanise and more recently hard plastic.
As a boy I use to look in these troughs to see the little "Water Boatmen" swimming around. Their correct scientific name is (Nononecta glauca) and I never realised it until I did the research, that they actually swim upside down. I called them water boatmen as they had what looked like an oar either side which they propelled themselves through the water with